Peel seal zipper tape

Abstract

A peel seal zipper tape for reclosable plastic bags or packages includes a first and a second mutually interlocking zipper profile disposed on a top surface of a laminated film strip. The top surface is formed by a layer of a sealant material. The laminated film strip also has a middle layer, or core, of a material stiffer than the first and second mutually interlocking zipper profiles, and may also have a bottom layer of a sealant material. In use, the laminated film strip is folded over, and the zipper profiles are interlocked with one another. In doing so, portions of the top surface of the laminated film strip face inwardly, so that the folded film strip may be closed with a heat seal. The outside of the folded peel seal zipper tape, that is, the bottom layer of sealant material is bonded to plastic sheet material from which reclosable plastic bags or packages are made. In the production of the bags or packages, the mutually facing portions of the laminated film strip are sealed together. The resulting seal gives a visual indication of having been broken when initially opened.

What is claimed is: 
     
       1. A peel seal zipper tape comprising a first and a second mutually interlocking zipper profile and a laminated film strip, said laminated film strip having a first layer of a first sealant material forming a top surface thereof and a second layer beneath said first layer, said zipper profiles being disposed on said top surface of said laminated film strip, a lateral edge of said laminated film strip, a first base web disposed between said first mutually interlocking zipper profile and said top surface of said laminated film strip extending to said laminated film strip lateral edge, said first base web being formed of a material different from said first sealant material and a second base web disposed between said second mutually interlocking zipper profile and said top surface of said laminated film strip. 
     
     
       2. A peel seal zipper tape as claimed in claim 1 wherein said first and said second mutually interlocking zipper profiles are extruded from polyethylene. 
     
     
       3. A peel seal zipper tape as claimed in claim 2 wherein said polyethylene is a low density polyethylene (LDPE). 
     
     
       4. A peel seal zipper tape as claimed in claim 1 wherein said first base web is extruded from polyethylene. 
     
     
       5. A peel seal zipper tape as claimed in claim 1 wherein said first layer of sealant material is formed of ethylene vinyl acetate (EVA). 
     
     
       6. A peel seal zipper tape as claimed in claim 1 wherein said second base web material is extruded from the same material as said first base web. 
     
     
       7. A peel seal zipper tape as claimed in claim 1 wherein said second base web is shorter that said first base web.